Using a hierarchical model to estimate risk-adjusted mortality for hospitals not included in the reference sample.

Objective: To provide a method for any hospital to evaluate patient mortality using a hierarchical risk-adjustment equation derived from a reference sample.

Data Source: American College of Surgeons National Trauma Data Bank (NTDB).

Study Design: Hierarchical logistic regression models predicting mortality were estimated from NTDB data. Risk-adjusted hospital effects obtained directly from models using standard software were compared with approximations derived from a summary equation and data from each individual hospital.

Principal Findings: Theoretical approximations were similar to results using standard software.

Conclusions: To allow independent verification, agencies using reference databases for hospital mortality "report cards" should publish their risk-adjustment equations. Similar hospitals not in the reference database may also use the published equations along with the approximations described to evaluate their own outcomes using their own data.